Harpoon Therapeutics Reports Clinical Progress Across All Four TriTAC® Pipeline Development Programs
HPN424 has shown confirmed partial response in treatment of metastatic castration-resistant prostate cancer in highest fixed dose cohort (160 ng/kg) of continuing Phase 1/2a dose escalation trial
Three of seven patients in highest fixed dose HPN424 cohort have shown PSA reduction
Dose escalation trials advancing for HPN536 and HPN217 with initial data readouts and initiation of expansion cohorts expected in 2021
Management to host clinical update webcast/call today, December 8, 2020, at 8 a.m. ET
”We are pleased to provide a trial update to our shareholders today, as well as outline our expectations for 2021. We have made significant progress in all of our clinical development programs in 2020,” stated
“We are pleased to report the activity we are seeing with HPN424 in late-stage prostate cancer patients in our highest fixed dose cohort tested to date,” said
Clinical Program Updates
(All data as of
Dose escalation continues in Phase 1/2a trial for HPN424 in the treatment of mCRPC. As of the
At the highest fixed dose tested to date, 160ng/kg, one patient out of 7 has experienced a confirmed partial response with tumor lesion reduction of 43%, and 3 of 7 patients have had serum PSA declines from baseline, including one patient with a PSA reduction greater than 50%.
HPN424 was generally well tolerated and cytokine-related adverse events have been manageable. Reported Grade 3 or higher adverse events have included cytokine release syndrome (CRS) (10%), ALT increase (11%) and AST increase (11%). CRS events and transaminitis have been transient and have not resulted in treatment discontinuation. Dose-limiting toxicities (DLTs) have been observed and have not limited escalation. A maximum tolerated dose (MTD) has not been identified. Presentation of Phase 1 data and initiation of an expansion cohort is planned for the first half of 2021. Interim data from this expansion cohort is anticipated by the end of 2021.
HPN536 (mesothelin TriTAC) Phase 1/2a clinical trial continues escalation. Dosing has occurred across 9 fixed-dose cohorts of 6 to 280ng/kg and 1 step dose cohort up to 600ng/kg. Tumor types treated include late-stage ovarian and pancreatic cancers and peritoneal mesothelioma. Enrolled patients had a median of four prior systemic therapies, and 66% of patients had progressive disease as best response to their most recent prior therapy. Pharmacokinetic analysis shows median half-life of more than 70 hours. Among the relapsed/refractory ovarian cancer patients with at least one post-baseline scan, 8 of 12 (67%) patients showed stability of target lesions.
HPN536 appears to be well tolerated. One CRS grade 3 occurred in the absence of dexamethasone premedication treatment. The CRS resolved, and the patient continued on study with dexamethasone premedication. As of
Dose escalation for HPN217 (BCMA TriTAC) Phase 1/2 clinical trial progressing rapidly. Relapsed/refractory multiple myeloma patients have been treated across 6 single-patient fixed dose cohorts of 5 to 810µg, reflecting a more than 100-fold increase in dose in 8 months. HPN217 has been well-tolerated, and no DLTs have been observed as of the
First patient dosing anticipated for HPN328 (DLL3 TriTAC) by the end of 2020. The first site is open and recruiting for the dose escalation portion of this Phase 1/2 clinical trial. In the first cohort, the patients will receive a flat dose of 15µg of HPN328 administered once weekly by intravenous infusion. Eligible patients include small cell lung cancer patients who have relapsed after platinum chemotherapy and patients with other tumors associated with DLL3 expression. Presentation of initial data is planned for the second half of 2021.
Webcast and Conference Call
Harpoon’s management will host a webcast and conference call at
About Harpoon Therapeutics
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This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “may,” “will,” “expect,” “plan,” “anticipate,” “target,” “estimate,” “intend” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Harpoon Therapeutics’ expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties that could cause Harpoon Therapeutics’ clinical development programs, future results or performance to differ significantly from those expressed or implied by the forward-looking statements. Forward-looking statements contained in this press release include, but are not limited to, statements about the progress, timing, scope, design and anticipated results of clinical trials, the timing of the presentation of data, the association of data with potential treatment outcomes, the development and advancement of product candidates, and the timing of development milestones for product candidates. Many factors may cause differences between current expectations and actual results, including unexpected safety or efficacy data observed during clinical studies, clinical trial site activation or enrollment rates that are lower than expected, unanticipated or greater than anticipated impacts or delays due to COVID-19, changes in expected or existing competition, changes in the regulatory environment, the uncertainties and timing of the regulatory approval process, the risk that initial or interim results from a clinical trial may not be predictive of the final results of the trial or the results of future trials, the risk that trials may be delayed and may not have satisfactory outcomes, and unexpected litigation or other disputes that impede clinical trial progress. Other factors that may cause Harpoon Therapeutics’ actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in Harpoon Therapeutics’ filings with the
Contacts:
Chief Financial Officer
650-443-7400
media@harpoontx.com
Westwicke ICR
Managing Director
858-356-5932
robert.uhl@westwicke.com
Source: Harpoon Therapeutics